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Patented July 12, 1927.

UNITED STATES PATENT OFFICE.

JOSEPH W. MEADOWCROFT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO ED-WARD G. BUDD MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA,

A CORPORATION OF PENNSYLVANIA.

ELECTRIC SWITCH.

Application filed January 18, 1922.

My invention relates to improvements in electric switches and concerns,more particularly, switches of that class adapted for use in connectionwith electric welding machines, but is not restricted to such use as itmay be used in any connection for which it may be adapted orappropriated.

One of the objects of my invention is to provide an electric switchmechanism which is very durable and etlieiont, even when the switch isused in situations which require that it be operated very rapidly andsubstantially continuously, and which has a long life so that the needfor replacen'ient or repair of the switch parts is greatly lessened.

.A further object of my invention is to provide a switch constructionwhich will withstand very successfully the destructive or deterioratingeffects of rapid and continuous operation.

Another object of my invention is to provide means for carrying off theheat generated in' the switch contacts by the passage of the current soas to prevent undue heating ofthe Working parts of the switch.

Another object of my invention is to provide simple and effective meansby which the contacts of an electric switch may be renewed very quicklyand easily.

A further object of my invention is to provide an electric switch havingmeans for cooling the switch contacts.

Further objects, and objects relating to details and economies ofproduction and operation, will definitely appear from the detaileddescription-to follow. In one instance, -I accomplish the objects of myinvention by the devices and means described in the followingspecification. My invention is clearly defined and pointed out in theappended claims. A structure constituting a preferred embodiment of myinvention is illustrated in the accompanying drawings, forming a part ofthis specification, in

which Fig. 1 is a perspective view of the head and a portion of theoperating lever or" an electric welding machine, showing a switchembodying my invention applied thereto.

Figure 2 is a longitudinal sectional View through the switch,

Figure 3 is a plan view of said switch, and

Serial No. 530,070.

Fig. 4 is a longitudinal, sectional View through one of the switchcontacts.

In the drawings, the same reference numerals refer to identical partsthroughout the several views.

In the pending application of Joseph Ledwinka for Letters Patent forautomatic electric welding machines, Serial No. 430,320, filed December13th, 1920, there is illustrated an electric welding machine which isused to produce, automatically, a series of spot welds in the workplaced or fed between the electrodes ot the machine. This machinecomprises a standard having a lower arm, carrying a fixed electrode, andan upper arm in which a plunger, carrying a movable electrode, isslidably reciprocated, to cause the movable electrode to approach thefixed one, by a. two-part operating lever. The inner part of theoperating lever is fixed to a shaft, which is connected to the plungerby a toggle link, and the outer part of the lever is pivoted'to theinner part. The two parts of the lever are held yieldingly in line witheach other by suitable spring means. The welding circuit is controlledby an automatic switch in which the closing and opening of the circuitis determined by the relative positions of the two parts of theoperating lever so that, when the movable electrode exerts apredetermined pressure on the work, the contacts of the switch move intoengagement with each other and the welding circuit is'closed, and, whenthis pressure is increased a predetermined amount, the contactsautomatically move away from each other and the circuit is opened. Theouter part of the operating lever is connected by asystem of links andlevers with a reciprocating pitman which is driven by an electric motor.The'operating lever is, consequently, actuated or oscillated rapidly,for instance, in actual practice, at a rate of about 120 strokes perminute.

I have found that the automatic switch, in a machine such as described,has a very short life and needs much repairing and replace seat of partsin order to keep it in operating condition. The copper contacts Weardown very quickly and have to be renewed and the insulating fibre burnsout and lets the parts of the switch work loose, resulting, frequently,in broken parts. The renewal of mounted. This plunger is .ti l, 91! d eah'e'sl in the It is among the special purposes of my invention toprovide a switch which is devoid of these objections and which willrequire very little repairing or replacement of parts, in other words aswitch which has a long life, even when operated under such tryingconditions as described above.

My invention consists in providing means f r c'ooling-the switchcontactsso as to carry V enerated by the passage of the current and y arcingandprevent the transmission of such heat to the working parts of. theswitch. may accomplish this by using hollow switch contacts connected ina llive Sy tem 0 t at a. o l ng fluid y be circulated therethrough.'llhe body of the switeh contactn ayhave a cooling chamber thereinprovided withan inlet and an outlet, the i'i letsand outlets of thevarious contaatsi liq ag qa eae q.t t-su a e. eech i that a coolinw' jedu'm maybe circulated Wa h them- T i ei oate ts'e e r id d-with ma ableslan e b -t d ta a'bly connected to the body of the contact,

- so, that they may be removed without distu b ng t e atter;-

r5191: e pla umy inyent I a illustrated an automatic switch suitable forwe in el tr c 'w li'l fi gmslunssand c e u i ins m od m n' at i e t enMy invention, however, not'to-ibelimited :or nestricted tp a switch'oftype as itl will finduse application inswltches' of, many ther'types.Inthe drawings accompanying this speciticati0 i,-I,"l1a,ve" illustratedan automatic switch construct-ion applied to an electricwelding-machine, which switch embodies my invention. Referring to thenumbered parts of t l e.dra,wing, I haveshown the head. 10, of;anhelectri'c welding machine, which head 1 1, in which s 'ournafd a,shaft, 12, connected by the toggle 111;, 13, with the plunger of themachiiie czgggy ingtlie in yableeleetrode. This aft-Z.) .1 afiq llflted;.8" m ans. of a -p i-at ire I -'.Qeim s ea the i n P 1, Y,l11( 5,l 1.,lSfiXQd on the shaft, 12, and the e te pa t, 115,-. the'inper. p t Thelever may b a tuated qro'sc' l lated either by hand or auto matical iy'q y' st amer ina lever ws a-" e m P n ing- 1 wh n to whic v Pr viouslyreferred, or by other suitable mech- 32. A pair of tensionsprings,

\ v,hich is pivoted, at 16, to

anism. The inner part, 14, of the lever is channcl-shaped so that aportion of the outer part, 15, lies within this channel. The two parts,1% and 15, of the operating lever, are yieldingly held in alignment witheach other by means of a spring, 19, interposed between the outer end ofthe part, 14;, and athumbnut. 20, screwed on the end ot' a rod, 17,which extends through the inner part, 14, and ispivotally connected tothe outer part, 15, of the lever, 18.

A contact-carrying arm, 22, is pivoted at 21, to the inner part, 14, ofthe operating lever and carries a pair of contact-clamping members, 23,which are insulated from each other and from the operating parts of theswitch. Each of these contact-clamping members, 23, carries a switchcontact, 24:, detachably secured therein by means of the set screws, 28,and electrically connected at with a lead, 26, connected in the weldingcircuit. The pivoted arm, 22, is provided with the rearwardly extendingportion,- 29, which engages beneath a lug or shoulder, 31, formed on anoverhanging portion of the inner part, 14, of the lever. A spring, 30,engaging this portion, 29, holds it against the" stop shoulder, 31,'soas to determine the forward position of the contacts, 2%. It will b'eseen that this arrangement permits the contacts, 2 1, and the arm whichcarries them to move rearwardly, against the pressure of spring, 30,when engaged by the onposing contacts of the switch.

.An arm, 32, is also pivoted to-the inner part, 14, ofthe operatinglever, at 33, and carries a contact-clamping member, in which a pair'otcontacts; 35, are detachably securedby-the set screws, 36: The contactsof this pair are electrically connected to each otherand, when thecontacts, 24, previously described, thecircuit will be closed, 'A- link,38, is pivoted to the part, 14, ot "the operating lever, by the pin, 15,"'d theupper end of said-link t 'pivotally c onnectedbya" pin,-54, tothe they are '1I 1 engagement with rearends of a pair of parallellinks,39, the

forward ends of whichjar'e pivotally connected by the pin, 40, to theswinging arm, 41, have their forwfard ends, connected to the pin, 40,-and their rear ends connected, at 42', to the fixed standard, 43. Ahousing, 4 1, has a downwardlyeexte nlding leg which is pivoted on thepin, 45,;and: another "downwardly-extendingleg, 46, at the forward endthereof, which is adapted to engage the part, 14, of the operating leverin or der to limit the rocking movement of the. housing, 44, around itspivot, 45, plunger, 47', works Within the'housing, '44, and has a stem,48, which extends through the bottom of therhousing andis connected tothe part, 15, of theope rting lever, by a link, 49, extending throughthe part, 14, and pivotally connected to the part, 15, at 50. A coilspring, 51, is placed within the housing, 44, between the base thereofand the plunger, 47, as shown in Fig. 2. The upper face of said plungerhas a tooth, 52, formed therein which coacts with a pawl, 53, pivoted onthe pin, 54, and yieldingly pressed into engagement with the plunger-bya. spring, 55.- \V hen a downward pull is exerted on the outer end ofthe outer part, 15, of the operating lever, the two parts of the levermove as one until the upper electrode of the welding machine engages thework. The resistance offered by the work to'the further movement of themovable electrode causes the outer part, 15,

of the lever to swing on the pivot, 16, relative to the inner part, 14,against the pres sure of the spring, 19. This swinging movement of theouter part of the operating lever, causes thehousing, 44, to swing onits pivot, 45', since it is connected with the outer part, 15, of theoperating lever through link, 49, stem, 48, plunger, 47, and coilspring, 51. During this stage of the movement, the link, 38, iscompelledto' swing on the pivot, 45, with the housing, 44, since thepawl, 53, hooks int-o the tooth, 52,;of the plunger, 47. The forwardswingingmovement of the link, 38, swings the arm, 32, -forwa rd, due tothe links, 39,. connecting, the link, '38, and the arm, 32, and thecontacts, 35, are brought intoengagement with the contacts, 24. Thisswinging movement of arm, 32, puts the springs, 41,under tension:'A-further swinging moven entof housing, 44,isprevented by thecontact-of the foot,.46, with the part, 14, of; the operating-Jeyer'and, a ,further movementof-lthe outer part, :15, of the operating lager;around ii.ts.,pivot', 16, compresses the spring 51, and; depresses theplunger, 47, withdrawin ith ieitooth,-52, thereof from engagement withthetpawl,.53, and breaking the connection betweemthe housing, 44,,andthe lin k,.38, so that-the arm, 32 is freeto fly backward, influenced bythe tension of springs, 41, carrying the contacts, 35, out of engagementwith the contacts, 24, and opening the welding circuit.

Each of the contacts, 24 and 35, in this switch, has a chamber, 56', inthe body portion thereof, and an inlet and outlet, 57 and 58,communicatingwithsaid chamber. These inlets andoutlets areconnected bysuitable conduits or tubes, 60, 61, 62, 63 and 64, so that. asuitablecooling medium may be circulated through the various chambers,56, of

the severalcontacts. The tubing is preferably arranged so that thesechambers are connected in series and the cooling medium, for instance,cooling water. may flow in through the tube, 64, and the inlet, 57', tothe chamber, 56, of one of the contacts. 24, out through the outlet, 58,and tube, 63, to the inlet,'57, of the chamber, 56,- of one of thecontacts, 35, from thence through the tube, 62, to the chamber, 56, ofthe other contact, 35, from thence through the tube, 61, to the chamber,56, of the remaining contact, 2'}, and from thcncc through the tube, 60,to the discharge. The contacts are all pi-a-Yided with removable contactpoints or ends, 37, each of which has a screw-threaded stem, 59, screwedinto the body portion of the contact, as shown in Fig. 4. As thesecontact points or ends become worn down in use, they may be removed veryquickly and easily by unscrewing them from the body portion of thecontact and they may be replaced by new points or ends.

I have found that, by the use of a cooling system for the switchcontacts, as described above, the objectionable features heretoforenoted in the operation of the switch, particularly at high speed, areeliminated. The switch does not break down in use and it is practicallyunnecessary to repair or replace the operating parts, with the exceptionof the contacts, which, of course, wear down in use. I find, however,that the life of these contacts is about twice as long as the life ofthe contacts formerly used and I believe this to be due to the fact thata large part of the heat generated in the contacts iscarried away by thecoolingsystem. Notpnly is the life of the contacts prolonged due to thecarryin away of the generated heat, but also to a large extent to theresistance and ca pacity shunt circuits which actually out down thearcing at the contact points themselves. These circuits, are thoseformed, respectively, by the series water circuit from one contact-ofthegap to thejotherthrough the ,bridging. contact points, and by ,the watersupply -connection connecting with one terminal and the, water dischargeconnection leading from the other terminal connecting with the sewer. Ialso find that my im- 'proved switch is so eliicient and so superior tothe switch heretofore used, that I may-increase thespeed of theautomatic welding machine very greatly, so as to get, approximately, 30%more welds per minute with it. This results in increased production atlower cost and, of course, is very desirable. As I have stated, thecontact points necessarily wear down in use and, in order to avoid thenecessity for disconnecting the contacts and the connections for thecooling system, I have provided the removable contact points or endswhich are detachably secured to the body portions of the contacts andmay be removed very quickly and easily and replaced by new points orends.

My invention has proven of considerable value in electric weldingmachines, especially those that are operated automatically andconsequently at high speed. However, this invention is applicable toother-electric switches and, therefore, I am not to be re-, stricted tothe details of the particular switch mechanism illustrated or to aswitch used in connection with an electric welder. I am aware that theembodiment of my invention, illustrated in the accompanying drawings,may be varied considerably without departing from the spirit thereofand, therefore, I claim my invention broadly, as indicated by theappended claims.

Having thus described my invention, what I claim as new and useful anddesire to secure by Letters Patent is:

1. An electric switch comprising a plurality of pairs of contact membersmovable into and out of contact with each other, means for moving saidmembers, and means for continuously circulating a cooling fluid in heattransferring relation to and through said contact members in series.

2. In an electric switch of the class described, a pair of contactmembers elect-rically and mechanically connected together, a second pairof contact members mechanically connected together but insulated fromeach other, said pairs of contact members being movable into and out ofcontact with each other, and means for continuously and uninterruptedlycirculating a cooling fluid successively through each of said contactmembers.

i 3. In an electric welding machine includ ing a primary circuit'therefor, pair of spaced apart contact members in one side of saidcircuit, aseeond' pair of contact; members electrically" connectedtogether and adapted to bridge said-first pair of contact members, andmeans for circulating a cooling'fi'nid through -said contact members insuccession beginning with one of said elec tricallyspaced"apart-'icontact members and ending with the-other of said'ele'ctrical-ly spaced aparfcontact members.

4L In ani'electfric sjwitch of the class described, a pair oficontactmembers rigidly connected" together but insulatedfrom each other, asecond pair of contact members rigidly and electricallyconnectedtogether, said second mentioned pair of'contactmembersbeingadapted to b'ridgesaid first mentioned pair of contactmer'nbersfand a circulating cooling system having its source connectedto one or said electrically insulated contact members audits =outl etcon- .nected to the other of said electrically insulate dcontact'members.

- 5: In an electric. switch of the class described, a plurality ofcontact members, a p ir of ports 'ineach'. of. said contact members,certain of said contact members being electrically connected togetherand the remaining of said contact members being in sulated from eachother, means connecting a port in one of said electrically connectedcontact members to a. port in the other of said electrically connectedcontact members,

and additional means connecting the other ports of said electricallyconnected contact members to corresponding ports in said electricallyinsulated contact members, respectively, whereby to effect a completecirculating system for a cooling medium.

6. A power control system comprising a circuit of high voltage, a powerconsuming device, a circuit breaker cont-rolling the supply of powerthereto, and a column of conducting fluid of relatively high resistancecirculating through the terminals of said breaker in series whereby thearc between the terminals is moderated by the resistance shunt somaintained and the heat of the arc is conducted away by the fluidcolumn.

7. A power control system comprising a circuit of high voltage, a powerconsuming device, a circuit breaker controlling the supply of powerthereto, and a column of water supplied through the grounded mains anddischarged to grounded sewers circulating through the terminals of saidbreaker whereby parallel paths of resistance and capacity are'introducedtherebetween.

8. A power control system comprising a source of high voltage, a powerconsuming device comprising the primary of an electric weldingtransformer, a circuit breaker controlling the supply of voltage to saidprimary, and a column of conducting fluid of relatively high resistancecirculating through the terminals of said breaker in series whereby theare between the-terminals is moderated by the resistance shunt somaintained and the heat of the arc is conducted away by the fluidcolumn.

9. A power control system for electric welding machines comprising awelding transformer having primary and secondary circuits, weldingelectrodes permanently connected in said secondary circuit, and acircuit breaker automatically operated in the functioning of them'a'chine tomake and break the primary circuit "for each weld madetogether with a circulating columndfelectrically and heat conductivefluid flowing through the terminals of the circuit breaker in series.

10. power control system for electric welding machines comprising awelding transformer having a primary circuit of relatively high voltageand a'secondarycii cuit of relatively low voltage, welding electrodespermanently connected in said secondary circuit of low voltage, acircuit breaker operating continuously durin the operation of themachine to connect and disconnect the primary circuit from the source ofpower, and a column of water circulating through the terminals of saidbre'alrer in series.

In testimony whereof, I afiix my signature.

JOSEPH- W. MEADOWCBOFT.

